Machine-switching telephone-exchange system.



J. N. REYNOLDS.

MACHINE SWiTCHING TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED SEPT. 7. 1915.

1,203,908. Patented Nov. 7, 1910.

Will? asses:

renn n men- JOHN N. REYNOTJDS, OF GREENWICH, CONNECTICUT, ASSIGN'OR, BY MESNE ASSIGN- MENTS, TO WESTERN ELECTRIC COMPANY,

NEW YORK. I

INCORPORATED, A CORPORATION OF MAOHIN E-SWITCHIN G TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent.

Patented Nov. 7, 11916.

Application filed September 7, 1915. Serial No. 49,220.

To all whom it may concern:

Be it known that 1, JOHN NEWBERRY REY- NOLDS, a citizen of the United States, residing at Greenwich, in the county of Fairfield and State of Connecticut, have invented certain new and useful Improvements in Machine-Switching Telephone-Exchange Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems employing line finders for extending calling lines to connecting c1rcuits, and wherein the finders are associated with calling lines by an extended starter wire. In such systems when the line finder connects with the calling line, mechanism associated with such finder operates to ex tend' the starter wire to the succeeding idle finder. It may happen,'however, that the finder set in motion by the calling party fails to connect with the calling line. Consequently such call is not extended. In addition, the other subscribers are without service due to the derangement of the starter wire.

The object of this invention is to obviate this difliculty, and the novelty resides in a circuit arrangement whereby, in case the finder overruns in either its primary or secondary movements, means is rendered operative to connect the starter wire through to the nextddle finder, and automatically cut the deranged finder out of circuit.

The invention will be more readily understood when described with reference to the accompanying drawing which shows only so much of a system as is necessary for a comprehension of this invention.

The subscribers lines are divided into groups and terminate in multiple terminals 39, 40 of finder switches, the number depending on the traffic. Each line is provided in the finder with a test terminal 41. The removal of the receiver by a calling party energizes the line relay 10, which by operating the relay 17 common to the group to which the calling line belongs, closes the circuit of the primary stepping magnet 30 of the finder. The brush shaft 26 of the finder carries a set of brushes 36, 37, 38 for each group of lines to which it has access. The finder then in a primary movement positions the proper set below multiples of the calling line group. The changeover operation then occurs to switch the secondary stepping magnet 42 into circuit to cause such set of brushes to wipe over the multiples 39, 40, 41 thereof. The test brush ing this operation and glzes the cut-off relays 12 of the lines of the calling group. When the cut-off relay 12 of the calling line is reached, the group relay 17 is deenergized and opens the secondary stepping circuit to stop the finder upon the calling line terminals.

The invention will be best understood by desclrlibing the operations involved in tracing a ca I The removal of the receiver by the calling party at substation A closes the following circuit to energize the line relay 10: free pole of battery, left winding of relay 10, conductor 11, left armature and back contact of cut-off relay 12, conductors 13, 14, line consuccessively enerductor a, sender S through the telephonic apparatus at substation A, line conductor 6, conductor 15, right armature and back contact of relay 12, conductor 16, right winding of relay 10 to ground. Relay 10 thereupon locks itself in series with a relay 17, common to this group of lines, over the following circuit: free pole of battery, left winding of relaylO, conductor 11, left armature and back contact of relay 12, conductors l3 and 14, left armature of relay 10, spring 18, conductor 19, left-armature and back contact of relay 20, conductor 21, relay 17 to ground. Relay 17 at its left armature and front contact locks itself to conductor 22, independent ofthe back contact of relay 20, and at its right armature and front contact energizes a slow relay 23 and grounds terminal 24 of the calling group on a group switch G, which group switch is carried by the finder, the brush 25 thereof rotating with the brush shaft 26 and being adapted to wipe over the multiples t of the line groups to which this finder has access.

Assuming that the finder apportioned to the line group to which the calling substation A belongs is idle, the following circuit is closed, upon the energization of the group relay 17, to energize the side switch escapement magnet 27 to release the side switch into the second position to initiate the secondary movement of the line finder, since no primary movement of such finder is necessary, it being understood that the line 38 is grounded durfinder apportioned to a line group, if idle, has a set of brushes 36, 37, 38 in operative relation to multiples 39, 40, 41 of such group: free pole of battery, armature and back contact of release magnet 28, conductor 29, primary magnet 30, conductors 31 and 32, side switch escapement magnet 27 conductor 33, side switch arm 2 and its first contact, conductor 34, brush 25 of the group switch G, group terminal 24 with which it is normally in contact, conductors 35, 51, right armature and front contact of group relay 17, to ground. Side switch escapement magnet 27 immediately releases the side switch into the second position. The primary magnet 30 does not energize by the closure of this circuit, due to its low resistance.

In position 2 the escapement magnet 27 is maintained energized over the following circuit: free pole of battery, armature and back contact of magnet 28, conductors 29 and 72, magnet 30, conductors 31, 32, magnet 27, conductor 33, arm 2 and its second contact, conductors 80, 73, spring 48, conductor 49, right armature and front contact of relay 23, conductors 50, 51, right armature and front contact of relay 17 to ground. In position 2 of the side switch, the following circuit is closed to drive brushes 36, 37, 38 of the line finder over the multiples 39, 40 and 41 of the calling line group: free pole of battery, armature and back contactof release magnet 28, conductor 29, secondary stepping magnet 42, conductor 43, arm 1 and its second contact, corductor 44, armature and back contact of magnet 42, conductors 45 and 46, armature \nd back contact of magnet 30, conductor 4 spring 48 now closed to its bottom contact, conductor 49, right armature and front contact of relay 23, conductors 50, 51, right armature and front contact of relay 17 to ground. The stepping magnet 42 makes and breaks its own circuit, thus driving the brushes 36, 37 and 38 over the multiples 39, 40 and 41. In position 2 of the side switch the arm 3 connects ground to the test brush 38 of the line finder over the following circuit: ground, right armature and front contact of relay 17, conductors 51, 50, right armature and front contact of relay 23, conductors 49 and 53, arm 3 and its second contact, conductor 54, to test brush 38. The cut-off relays 12 of the lines of the calling group are energized in succession as the brush 38 engages the multiples 41 of such lines. When the terminal 41 of the calling substation is reached, the energization of its cut-off relay 12 opens the circuit traced for the group relay 17. This relay, in retracting its right armature, removes ground from the circuit traced for the secondary stepping magnet 42, thus stopping the finder upon the calling line terminals, and also removes ground from the circuit traced for escapement magnet 27, which releases the side switch into position 3. The calling line is now extended over brushes 36, 37 and conductors 55, 56 either to a first selector or to an operators position (not shown). Arm 1 extends starter wire 44 over conductor 66 to the next idle finder.

Assuming that another call originates in a line of the group to which substation A belongs when the finder shown, allotted to such group, is busy, the line relay 57 of such line is energized dueto the removal of the receiver at the substation. Group relay 17 is thereupon energized over the following circuit: free pole of battery, left winding of line relay 57, conductor 58, left armature and back contact of cut-0E relay 59 of such line, conductor 60, armature of relay 57, spring 61, conductor 62, contact 63 and spring 18 of relay 10, conductor 19, left armature and back contact of relay 20, conductor 21, group relay 17 to ground. Relay 17, by attracting its left armature, locks itself to conductor 22 as before, and by the attraction of its right armature grounds the extended starter wire'as follows: ground,

right armature and front contact of relay 17 conductors 51 and 50, right armature and front contact of relay 23, conductor 49, spring 48, conductors 73, 47, armature and back contact of magnet 30, conductors 46, 45, armature and back contact of magnet42, conductor 44, side switch arm 1 and its third contact, starting conductor 66 to battery,

through the primary stepping magnet of the next idle finder. This circuit may be traced by assuming the finder shown to be the next idle finder. The circuit therefor leads into such finder by way of conductor 67, left armature and back contact of relay 23, conductors 69 and 70, relay 20 to free pole of battery. Relay 20, by attracting its left armature, removes the control of relay 17 of this line group from the subscribers thereof. In parallel with relay 20 the following circuit is closed for the primary stepping magnet of such finder: conductors 69, 71, right armature and back contact of relay 23, conductor-49, spring 48, conductors 73, 47, armature and back contact of magnet 30, conductors 46, 45, armature and back contact of magnet 42, conductor 44, arm 1 and its first contact, conductor 31, primary magnet, conductors 72, 29, armature and back contact of release magnet, free pole of battery. The stepping magnet thereupon makes and breaks its own circuit, thus causing the brush of the group switch G to wipe. over the group multiple terminals t thereon. When the terminal t, grounded at the right armature and front contact of relay 17, is reached, the following circuit is closed for the side switch escapement magnet, corresponding to 27, of said finder: free pole of battery, armature and back contact of the release magnet, conductors 29, 72, magnet 30, conductors 31, 32, magnet 27, conductor 33, arm 2 audits first contact, conductor 34, brush 25 to multipleterminal t of the callmg group on this finder group switch, to ground at the right armature and front contact of the group relay 17. The armature of magnet 27 is held attracted by the closure of this circuit, and side switch escapement magnet releases the side switch into position 2, in which the following circuit is closed to maintain escapement magnet 27 energized: free pole of battery, armature and back contact of magnet 28, conductors 29, 72, magnet 30, conductor 31, conductor 32, magnet 27, conductor 33, arm 2 and its second contact, conductor 80, conductor 73, spring 48, conductor 49, right armature and back contact of relay 23 of the, group normally served by the finder, conductor 71, conductor 69, left armature and back contact of relay 23, conductor 67, conductor 66, arm 1 of the finder shown and its third con tact, conductor 44, armature and back contactof magnet 42, conductor 45, conductor 46, armature and back contact of magnet 30, conductor 47, conductor 73, spring 48, conductor 49, right armature and front contact of relay 23, conductor 50, conductor 51, and armature and front contact of relay 17 to ground.

In position 2 the following circuit is closed for the secondary stepping magnet 42 to cause the brushes 36, 37, 38 of such finder so positioned to wipe over the multiples 39, 40, 41 of such group: free pole of battery, armature and back contact of the release magnet of such finder, conductor 29, secondary stepping. magnet 42, conductor 43, arm 1 and its second contact, conductor 44, armature and back contact of magnet 42, conductor 45, armature and front contact of magnet 27 conductor 73, spring 48 and its lower contact, conductor 49, right armature and back contact of relay 23 .of the line group served by such finder, conductor 71, conductor 69, left armature and back contact of relay 23, conductor 67, conductor 66, side switch arm 1 and its third contact, conductor 44, armature and back contact of magnet 42, conductor 45, conductor 46, ar-

of magnet 30, conandits lower contact, conductor 49, right armature and front contact of relay 23, conductor 50, conductor 51, right armature and front contact of relay 17 to ground. The arm 3 of such finder mature and back contact in position 2 grounds the test brush 38.

thereof. Consequently when the multiple 41 of the calling substation is reached, the following circuit is closed to energize the cut-off relay 59: ground, right armature or relay 17, conductor 51, conductor 50, right armature and front contact of relay 23, con- Upon the 11th shaft, the spring 48 is allowed to disengage ceeding idle finder with ductor 49, spring 48, conductors 73, 47 right armature and back contact of magnet 30, conductor 45, armature and back contact of magnet 42, conductor 44, arm 1 and its third contact, conductor 66, conductor 67, left an mature and back contact of relay 23, conductor 69, conductor 71, right armature and back contact of relay 23, conductor 49, conductor 53, arm 3, conductor 54, brush 38, multlple 41 of the calling line, conductor 74, cut-oif relay 59,- free pole of battery. Relay 59, by attracting its left armature, opens the circuit for group relay 17, which, in retracting its right armature, removes ground from the secondary magnet 42, the side switch magnet 27 andthe relay 20 of such finder. The side switch magnet thereupon releases the side switch to position 3, thus extending the calling line to a first selector, or an operators position (not shown).

Assuming now that after the primary stepping magnet 30 or the secondary stepping magnet 42 had initiated either the primary or secondary movements of the line finder, but that for some reason or other the stepping circuit for either of these magnets had not been opened at the proper time. primary step of the brush itself from its lower contact and engage its upper contact. Similarly, upon the tenth step of the secondary stepping magnet 42, this spring is transferred from its lower to its upper contact. For simplicity, the spring 48 is not shown in the position it actually assumes on the switch structure but is shown schematically, springs actuated by shafts to control circuits being well known in the art. Consequently, if a finder having been set in motion fails to function properly, the switch in trouble is cut out of circuit, and the starter wire automatically extended through it into the next idle line finder. It will be noted that this result is accomplished by means of only a single spring 48 and its associated contacts. The circuit for the next idle finder, in case a switch overruns, is then as follows: right grounded armature of group relay 17 conductor 51, conductor 50, right armature and front contact of relay 23, conductor 49, spring 48 and its upper contact, conductor 65 to the starting conductor 66, and from thence over the circuit traced to the primary magnet of the next idle'finder. This finder then begins to hunt for the calling line and having connected thereto associates the sucthe remaining lines when its side switch arm 1 moves into position 3.

Upon the first primary step of the line finder the primary off-normal spring 75 is transferred from its lower to its upper contact. The hanging up of the receivers by the subscribers, or some act on the part of &

the operator in disestablishing the connec tlon, grounds conductor 76, which ground is extended by off-normal springs 75, conductor 76, right armature and back contact finders to which said lines are multipled,

driving magnets therefor, an extended starter wire for associating an idle finder with said lines, and means actuated upon the initiation of a call for closing a circuit including said starter wire to initiate travel of said finder, a contact operated by the finder-brush shaft when it is driven more than a predetermined distance by said magnet for extending said starter wire to the next idle finder.

2. In a telephone exchange system, the combination with a plurality of lines divided into groups, finders to which said lines are multipled, a magnet for driving said finder in a primary direction to select the calling group, a magnet for driving said finder in a secondary direction to select the calling line therein, an extended starter wire for associating an idle finder with said line groups, and means actuated upon the initiation of a call for closing a circuit including said starter wire to initiate travel of said finder, of means operated in case such finder is driven more than a predetermined distance by either magnet for extending said starter wire to the next idle finder.

3. In a telephone exchange system, the combination with a plurality of lines divided into groups, finders in which said lines terminate in multiple contacts, the shaft of said finder having brushes adapted to engage therewith, a magnet'for driving said shaft in a primary direction to select the calling group, a magnet for driving said shaft in a secondary direction to select the calling line therein, an extended starter wire for associating an idle finder with said line groups, and including the primary magnet of such finder, and means actuated upon the initiation of a call for closing the circuit of said magnet over said starter wire, of a contact closed by said shaft in case it is driven more than a predetermined distance by either magnet for extending said starter wire to the next idle finder.

In witness whereof, I hereunto subscribe my name this 3rd day of September A. .D. 1915.

JOHN N. REYNOLDS. 

